Crossworks implementation of USB bootloader

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by williamjsell on Fri Jan 25 12:11:05 MST 2013
firstly, I searched to see if there was a port of the AN10866 USB bootloader over to Rowley Crossworks in the public domain, but no luck here, so if anyone has done this... :) ...so figured this should not be too hard, but I ran into a couple of snags.  The keyword __packed is not supported by Crossworks, so I used the #pragma pack(1), which should work the same way.  I then ran into a code issue. 

the declaration:


the initialization:

pD = (USB_COMMON_DESCRIPTOR *)USB_ConfigDescriptor;

The Keil compiler builds fine, but Crossworks bitches on this statement:

(uint8_t *)pD += ((USB_CONFIGURATION_DESCRIPTOR *)pD)->wTotalLength;

with the message

"lvalue required as left operand of assignment"

Makes sort of sense, it wants pD to reference a member of the structure it points to, even though it is being cast to uint8_t.  Looks like the author is attempting to increment the pointer by wTotalLength.  I am a little lost here.  Firstly, looks like it should work, but I tried several different iterations and I get the same message...any ideas?